Protein Background and Biological Function

Heat shock protein 47 (Hsp47), encoded by the SERPINH1 gene, is a collagen-specific molecular chaperone that resides in the lumen of the endoplasmic reticulum (ER). Unlike classical heat shock proteins that act broadly, Hsp47 exhibits a unique and highly selective interaction with procollagen, binding to the folded triple-helical regions and preventing premature aggregation during biosynthesis and intracellular transport.

Hsp47 belongs to the serpin (serine protease inhibitor) superfamily by structural classification; however, it does not exhibit protease inhibitory activity. Instead, it functions exclusively as a chaperone. Upon procollagen's exit from the ER to the Golgi apparatus, the lower pH environment triggers dissociation of Hsp47 from its client procollagen, allowing further processing and secretion.

Genetic knockout studies in mice have demonstrated that loss of Hsp47 is embryonic lethal, underscoring its indispensable role in collagen biosynthesis and organismal development. Mutations in SERPINH1 in humans are associated with a recessive form of osteogenesis imperfecta (brittle bone disease), further highlighting its physiological importance.

Research Applications

Recombinant Human Hsp47 Protein (rp365928) is a versatile reagent suitable for multiple experimental applications in the fields of collagen biology, fibrosis, protein folding, and structural biochemistry. Key applications include:

• In vitro Binding and Interaction Studies: Recombinant Hsp47 can be used in pull-down assays, surface plasmon resonance (SPR), and isothermal titration calorimetry (ITC) to characterize its interaction with procollagen peptides or triple-helical collagen mimetics.
• Fibrosis Research: Given the upregulation of Hsp47 in fibrotic tissues (hepatic, pulmonary, renal), the recombinant protein serves as a positive control, immunogen, or functional reagent in fibrosis model studies and drug screening assays targeting the collagen chaperone pathway.
• Biochemical Assays: Used as a standard or control in ELISA, Western blotting, and immunoprecipitation experiments requiring validated Hsp47 protein.
• Structural Studies: Suitable for structural biology investigations, including crystallography and cryo-electron microscopy studies of chaperone–client complexes.
• Cell-Free Systems: Can be incorporated into reconstituted cell-free collagen folding assays to dissect the mechanistic contributions of Hsp47 to procollagen quality control.

Researchers in academic, pharmaceutical, and biotechnology settings will find this recombinant protein valuable for mechanistic, translational, and drug discovery research programs targeting collagen-associated pathologies.

Storage, Handling, and Reconstitution Guidelines

To maintain the biological activity and structural integrity of Recombinant Human Hsp47 Protein, adherence to the following storage and handling guidelines is strongly recommended:

• Storage Temperature: Store lyophilized or liquid protein preparations at −20 °C or −80 °C as specified on the product datasheet. Avoid repeated freeze–thaw cycles, which can cause protein aggregation and loss of activity.
• Aliquoting: Upon first thaw, aliquot the protein into single-use volumes to minimize freeze–thaw stress. Clearly label aliquots with date and concentration.
• Reconstitution: If supplied in lyophilized form, reconstitute in sterile, ultrapure water or the recommended buffer (refer to the specific product datasheet for buffer composition and recommended concentration). Allow the lyophilized cake to dissolve completely by gentle swirling — do not vortex vigorously.
• Working Conditions: Keep protein on ice during experimental procedures. Avoid prolonged exposure to room temperature. Use low-protein-binding tubes and pipette tips to minimize adsorptive losses.
• Carrier Proteins: For highly dilute working solutions, consider adding a carrier protein such as BSA (0.1–0.5%) to stabilize the protein and prevent non-specific adsorption to surfaces.
• Sterile Filtration: If the protein will be used in cell-based assays, ensure the solution is filter-sterilized through a 0.2 µm membrane under aseptic conditions.

Always consult the product-specific Certificate of Analysis (CoA) and datasheet provided with each lot for precise storage conditions, concentration, purity, and activity data.

Role of Hsp47 in Fibrosis and Disease

Hsp47 has emerged as a clinically relevant biomarker and therapeutic target in fibrotic diseases. Its expression is tightly correlated with collagen production; in fibrotic conditions, both collagen and Hsp47 are markedly upregulated in activated fibroblasts and myofibroblasts.

Liver Fibrosis and Cirrhosis: Elevated Hsp47 expression is observed in hepatic stellate cells during liver fibrosis progression. Experimental silencing of Hsp47 using siRNA-loaded delivery systems has shown promise in reducing fibrotic collagen deposition in preclinical animal models, positioning Hsp47 as a therapeutic target for liver fibrosis.

Pulmonary Fibrosis: In idiopathic pulmonary fibrosis (IPF), Hsp47 is upregulated in lung fibroblasts, contributing to excessive extracellular matrix (ECM) accumulation. Research using recombinant Hsp47 helps elucidate mechanistic pathways driving ECM remodeling.

Renal Fibrosis: Similar upregulation of Hsp47 has been documented in renal tubular and interstitial fibrosis models, suggesting a conserved pathological role across organ systems.

Osteogenesis Imperfecta (OI): Loss-of-function mutations in SERPINH1 cause a rare recessive form of OI characterized by severe skeletal deformities, underscoring Hsp47's non-redundant role in collagen quality control in bone tissue.

Recombinant Human Hsp47 Protein (rp365928) is an essential reagent for researchers investigating these disease mechanisms and developing therapeutic interventions targeting the Hsp47–collagen axis.